SEATTLE (AP) — An Army staff sergeant confirmed to investigators that he received a phone call from a worried father last year warning that soldiers in his son’s platoon were deliberately killing Afghan civilians. However, Staff Sgt. James Michael Beck said he didn’t report the phone call to anyone because there was no standard operating procedure for doing so, according to a statement obtained by The Associated Press. Beck said he was working in the operations center at Joint Base Lewis-McChord south of Seattle on Feb. 14, 2010, when he received a call from Christopher Winfield of Cape Coral, Fla., who told him soldiers in his son’s platoon had already killed one civilian and were planning to kill more. Winfield said his then 21-year-old son, Spc. Adam Winfield, was being pressured to join the plot, and the younger Winfield was scared that his colleagues would hurt him if he didn’t go along, according to the statement. Army prosecutors allege two more Afghan civilians were subsequently killed, one during a patrol in February and another in May, in a brutal plot led by Staff Sgt. Calvin Gibbs and Cpl. Jeremy Morlock. Winfield is charged with joining Gibbs and Morlock in the final killing. He admitted in a videotaped interview that he took part and said he feared the others might kill him if he didn’t. “I took a man from his family,” he said in the interview. “I don’t know if it was my bullets that killed him or the grenade that killed him, but I was still part of it.” Winfield is one of five soldiers charged with murder and conspiracy to commit murder in the case, which includes some of the most serious war crimes allegations to arise from the Afghan war. Attorney Eric Montalvo, who represents Spc. Winfield, recently disclosed Beck’s statement to The Associated Press. Beck told Army investigators he did not report the call to anyone or note it in a staff duty journal because "there is no SOP for reporting telephonic incidents of misconduct from unofficial sources." Instead, he advised Winfield’s father that his son should alert his chain of command. "I assured the father that no chain of command in the Army would sanction or allow such activity and that if his son made the chain of command aware, that they would take care of him and the offending soldiers accordingly," Beck said. Spc. Winfield did not follow that advice, later saying he feared reprisals. Christopher Winfield first told the AP last September that he tried to alert the Army to the plot the same day his son sent him Facebook messages describing it. He provided copies of the messages, as well as phone records showing calls to numbers at Lewis-McChord. Beck’s statement is the first corroboration of the content of the 12-minute conversation he and Winfield had. At Winfield’s court martial, scheduled for late March, the Army is seeking to bar any evidence that he or his family ever tried to blow the whistle on the plot, calling any such efforts irrelevant hearsay. "Statements the accused made to his parents in January and February generally disapproving of murder ... are irrelevant to his conduct in May 2010," Capt. Andre Leblanc wrote in a motion filed this month. Though duress is not a legal defense to a murder charge, Montalvo said Winfield’s decision to alert his parents showed he was not a willing participant in any conspiracy. "How is it not relevant that he tried to report this?" Montalvo said. "But for the Army’s inaction, two more murders would not have occurred." Montalvo said he has been told by Army prosecutors that Beck was punished for his handling of Christopher Winfield’s call. However, the Army has not given him details of the punishment, and Montalvo said he has not been allowed to question Beck, who was transferred to Korea sometime after giving his statement last Sept. 22. The Army declined to discuss Beck’s handling of the call, saying it wanted to protect the integrity of the case as well as the rights of the accused. "An investigation into reporting procedures at the Installation Operations Center was conducted and is now complete," Maj. Kathleen Turner, a base spokeswoman, said in an e-mail Thursday. "However, those findings may be relevant to the court-martial of Spc. Winfield." The three unarmed Afghan men were killed during patrols in Kandahar province. Prosecutors say Gibbs, of Billings, Mont., put together a team of colleagues he could trust and devised "scenarios" for killing civilians, typically by pretending they were enemy combatants. Gibbs insists all of the killings were legitimate, but Morlock, of Wasilla, Alaska, gave extensive statements saying he and others slaughtered for no reason. Soldiers said Gibbs collected fingers from Afghan corpses and illicitly obtained weapons that he could drop next to the bodies of civilians to make them appear to be fighters. Several soldiers were accused of passing around photos of mangled corpses as though they were trading cards. The other defendants are Pvt. 1st Class Andrew Holmes of Boise, Idaho, and Spc. Michael Wagnon II of Las Vegas, Nev. Beck defended his conduct to a lieutenant colonel conducting the review. "I did tell (Winfield) that that if the avenues I gave him did not provide him satisfactory results, he was more than welcome to call the operations center back for further assistance," he said. "As far as I’m aware, he never did." Christopher Winfield has told the AP as well as Army investigators that Beck told him his son should either report the issue to his chain of command or "keep his head down" until the deployment ended, when he could report to officials at Lewis-McChord. Beck’s statement makes no reference to the latter advice. Martin L. Cook, a military ethics expert at the United States Naval War College in Newport, R.I., said that Beck could have done more to report the phone call, but it would have been irregular for a relatively low-ranking sergeant to call officers who could have effected an investigation. Christopher Winfield or Spc. Winfield also could have done more to blow the whistle, he said, with the simplest being Spc. Winfield taking the allegations up his chain of command. "It’d be a long way around for the information to get from that staff sergeant all the way to the chain of command in Afghanistan," Cook said. "He probably felt he’d been effective in the advice he had given."